One of our favorite questions from readers for
Economics in Plain English was deceptively simple: What, after all, is
money? And what sets it apart from something that's simply valuable? A
big abstract idea like this called for a hands-on experiment.

In this episode, business editor Derek Thompson pays a visit to a
branch of EagleBank in Arlington, VA, to bother the world's friendliest
bank teller with a series of dumb requests. As goofy as it seems, this
little experiment is a helpful way to illustrate three essential
functions of money: a store of value, a unit of account, and a medium of
exchange. But you'll have to watch to see why.